The study found that endurance athletes who extended their sleep time by 90 minutes for three days improved performance by 3 percent in a 60-minute time trial.

The researchers recommend sleeping more than 8 hours a night to optimize endurance performance.

I’ve always been able to sleep like a log for a good seven hours a night. Back when I was training for Ironman triathlons? I sacked out like a deposit from the petrified forest for a solid nine, sometimes 10 hours a day. Now that I’m older I make a habit of aiming for at least eight hours of shut eye during particularly draining training blocks.

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Seems I’m in good company: Perennial Super Bowl stud Tom Brady famously turns in by 9 p.m. every night to clock at least nine hours of recovery slumber, and pro golfer Michelle Wie, who claimed to have once slept 16 hours straight, swears by at least 10 to feel on her game.

The health detriments of short sleep are clear—it has been linked to everything from weight gain to heart disease to depression. But as for the performance benefits of shuteye? Funny thing is that though numerous studies have examined the benefits of regularly getting more sleep on ball and skill sports like football, basketball, and tennis, they haven’t really put endurance athletes to the test…until now.

In a recent study published ahead of print in Medicine & Science in Sports & Exercise, a group of exercise scientists from Australia and Singapore examined the effects of both sleep extension and restriction across three nights on endurance cycling performance.

The researchers recruited nine competitive endurance cyclists and triathletes and put them through a series of endurance tests while manipulating their nightly amount of sleep, first allowing them their normal 6.5 to 7 hours of sleep a night; then extending their sleep by 30 percent, so they were sleeping an average of 8.25 to 8.5 hours a night; and again after restricting their sleep 30 percent, leaving them with just under 5 hours of sleep a night.

For the endurance tests, the riders had to perform time-trials, pedaling until they achieved a set amount of work designed to simulate what they would produce during an hour-long time trial.

Compared to when they got their normal amount of shut-eye, the athletes were considerably slower after just two nights of sleep restriction, completing their time trial in an average of 60.4 minutes versus 58.8 minutes—a 3 percent decline in performance.

On the other hand, they significantly improved following three nights of extra sleep, finishing their time trial an average of nearly two minutes faster (58.7 minutes versus 56.8 minutes)—a 3 percent improvement in performance.

The athletes reported the same rating of perceived exertion—the time trial felt just as hard—regardless of their sleep status. However, their mood and “psychomotor vigilance” (a.k.a. sustained attention and reaction time) both improved with more sleep and were hindered by sleep restriction.

The authors concluded that “cumulative sleep time affects performance by altering the perceived exertion of a given exercise intensity.”

In other words, getting more sleep makes it easier to crank up your wattage without feeling like you’re suffering more or doing more work.

Can’t swing more than eight hours in the sack on a regular basis? No sweat. Though the riders’ performance increased, their sleep quality and efficiency took a bit of a dip during the week of sleep extension, which indicates that a lesser amount of sleep extension would likely do the trick, says study author Spencer Roberts, Ph.D. candidate at Deakin University in Melbourne, Australia.

“We know that many athletes do not achieve more than eight hours of sleep consistently. In fact, even at the very elite level, athletes often get less than seven hours of sleep per night due to the challenges of training and competition like travel and anxiety,” says Roberts.

So instead of stressing about trying to squeeze in more sleep when life is hectic, get as much shuteye as you can when you can, and use sleep extension as a secret weapon when you need it, says Roberts.

By extending your nightly rest by 30 percent in the days leading up to a big event, that next PR might feel easier than ever.

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